Protection mechanisms for multi-tiered spectrum access systems

ABSTRACT

A shared spectrum manager (SSM) may enable spectrum access for Tier 2 Users (T2Us) and Tier 3 Users (T3Us) while provisioning quality of access (QoA) in a dynamic shared spectrum environment while ensuring sufficient spectrum and interference protection for Tier 1 Users (T1Us). The SSM may enable new user spectrum authorizations by sending, to a regulator, a request for administrative information, and receiving, from the regulator, a policy and user authorization information for at least one user. The SSM may register a T2U with or without contacting the regulator. The SSM may perform quality based admission control by receiving periodic measurements from a master device of each T2U with an active frequency assignment indicating a Quality of Operation (QoO) experienced by the respective T2U, maintaining a map of an effective QoOs for a plurality of T2Us, and categorizing protection contours associated with each of the plurality of T2Us.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/891,225, filed Oct. 15, 2013, the contents of which are herebyincorporated by reference herein.

BACKGROUND

The growth of wireless traffic has been significant in the last decade.Studies predict that the tremendous worldwide growth in the market sizeof mobile broadband services will continue. For example, certainpredictions estimate that the mobile broadband market may grow from onebillion users in 2012 to as many as eight billion users by 2015. Inaddition, global mobile data more than doubled for the fourth year in arow in 2011, and it may continue to do so through 2016. Thus, additionalspectrum may be beneficial and necessary to accommodate increased mobilebroadband use.

Spectrum use may be based on exclusive utilization of dedicated bands.Additional spectrum for mobile broadband has been created by re-farmingor repurposing of spectrum, for example, by moving incumbents to otherbands. Examples of this include the 2.5 GigaHertz (GHz) band in manyparts of the world, and more recently with clearing of parts of theultra-high frequency (UHF) band due to the digital switchover, known asDigital Dividend.

The practice of repurposing has become more difficult and less feasibledue to difficulties of finding incumbent services that may be moved toother bands. In particular, repurposing of bands where existing servicesare widely in use may be an extremely costly and lengthy undertaking, asconfirmed by a recent National Telecommunications and InformationAdministration (NTIA) report that concluded that potential repurposingof the 1755-1850 MegaHertz (MHz) band would take ten years and costaround eighteen billion dollars. As a result, regulators are consideringmethods other than repurposing to obtain the new spectrum that willsolve the bandwidth crunch.

SUMMARY

A shared spectrum manager (SSM) may enable spectrum access for Tier 2Users (T2Us) and Tier 3 Users (T3Us) while provisioning quality ofaccess (QoA) in a dynamic shared spectrum environment while ensuringsufficient spectrum and interference protection for Tier 1 Users (T1Us).The SSM may enable new user spectrum authorizations by sending, to aregulator, a request for administrative information, and receiving, fromthe regulator, a policy and user authorization information for at leastone user. The SSM may register a T2U with or without contacting theregulator. The SSM may perform quality based admission control byreceiving periodic measurements from a master device of each T2U with anactive frequency assignment indicating a Quality of Operation (QoO)experienced by the respective T2U, maintaining a map of an effectiveQoOs for a plurality of T2Us, and categorizing protection contoursassociated with each of the plurality of T2Us.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A;

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A;

FIG. 2 shows a comparison of example spectrum use models;

FIG. 3 shows a hierarchical three-tier model for shared spectrum accessto federal spectrum;

FIG. 4 shows a system diagram of a shared spectrum access system withthree tiers of access;

FIG. 5 shows a block diagram of an example shared spectrum system forproviding Quality of Service (QoS) and Quality of Access (QoA) to Tier 2Users;

FIG. 6 shows a signal flow diagram of an example procedure including aT2U registration phase, and a T2U spectrum request and assignment phasebetween at least one T2U and an SSM;

FIG. 7 shows a signal flow diagram of an example administrativeprocedure between an SSM and a regulator;

FIG. 8 shows a signal flow diagram of an example T2U registrationprocedure;

FIG. 9A shows a system diagram of an example of a shared spectrum accesssystem with three tiers of access and protection contours.

FIGS. 9B and 9C show signal flow diagrams of example T2U and T3Uassignment procedures using protection contours;

FIG. 10 shows a flow diagram of an example QoA event detectionprocedure;

FIG. 11 shows a frequency diagram of an example use of a band passfilter to detect the cause of adjacent channel leakage;

FIG. 12 shows a system diagram of an example QoA event resolutionprocedure;

FIG. 13 shows a signal flow diagram of an example TTL renewal procedurefor a T2U/T3U in communication with an SSM;

FIG. 14 shows a signal flow diagram of an example TTL renewal procedurefor a T2U/T3U in communication with an SSM;

FIG. 15 shows a timing diagram of an example TTL renewal procedure witha missing evacuation confirmation;

FIG. 16 shows a timing diagram of another example TTL renewal procedurewith a missing evacuation confirmation;

FIG. 17 shows an example 3-tiered spectrum model in a location where atier 1 user (T1U) makes a certain amount of spectrum available for lowerlayers;

FIG. 18 shows a signal flow diagram of an example reassignment requestprocedure;

FIG. 19 shows a signal flow diagram of an example T2U trafficinformation collection procedure for prediction to be used in bufferdimensioning;

FIG. 20 shows a signal flow diagram of an example of a periodic spectrumuse procedure for a T1U;

FIG. 21 shows an example 3-tiered spectrum model where a T1U needs somebandwidth back that has been assigned to lower tier users; and

FIG. 22 shows a signal flow diagram of an example spectrum reclaimprocedure for a T1U.

DETAILED DESCRIPTION

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the other networks 112. By way of example, the base stations 114a, 114 b may be a base transceiver station (BTS), a Node-B, an eNode B,a Home Node B, a Home eNode B, a site controller, an access point (AP),a wireless router, and the like. While the base stations 114 a, 114 bare each depicted as a single element, it will be appreciated that thebase stations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple-output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as Institute of Electricaland Electronics Engineers (IEEE) 802.16 (i.e., WorldwideInteroperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1×,CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95(IS-95), Interim Standard 856 (IS-856), Global System for Mobilecommunications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSMEDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 106.

The RAN 104 may include eNode-Bs 140 a, 140 b, 140 c, though it will beappreciated that the RAN 104 may include any number of eNode-Bs whileremaining consistent with an embodiment. The eNode-Bs 140 a, 140 b, 140c may each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNode-Bs 140 a, 140 b, 140 c may implement MIMO technology. Thus,the eNode-B 140 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNode-Bs 140 a, 140 b, 140 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1C, theeNode-Bs 140 a, 140 b, 140 c may communicate with one another over an X2interface.

The core network 106 shown in FIG. 1C may include a mobility managementgateway (MME) 142, a serving gateway 144, and a packet data network(PDN) gateway 146. While each of the foregoing elements are depicted aspart of the core network 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 142 may be connected to each of the eNode-Bs 142 a, 142 b, 142 cin the RAN 104 via an S1 interface and may serve as a control node. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 142 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eNode Bs 140 a,140 b, 140 c in the RAN 104 via the S1 interface. The serving gateway144 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices. An access router (AR) 150 of a wireless local area network(WLAN) 155 may be in communication with the Internet 110. The AR 150 mayfacilitate communications between APs 160 a, 160 b, and 160 c. The APs160 a, 160 b, and 160 c may be in communication with STAs 170 a, 170 b,and 170 c.

The core network 106 may facilitate communications with other networks.For example, the core network 106 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 106 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 106 and the PSTN 108. In addition, the corenetwork 106 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatmay be owned and/or operated by other service providers.

Methods and apparatuses to use shared spectrum are described herein.Spectrum may be shared using a tiered hierarchy (e.g. with two, three,or more tiers of users) and may be used by wireless applications thatmay need to provide certain Quality of Service (QoS).

Most of the spectrum bands are currently not fully utilized in allplaces or at all times, and thus portions of spectrum bands may be madeavailable for other use in a shared manner on a geographical and/or timebasis. New technical solutions are emerging to enable sharing in bandsthat were previously not shared. Therefore, sharing is being seen as afeasible mechanism or tool that may complement repurposing andeffectively increase the amount of spectrum in use.

The recent advent of small cells may increase the feasibility ofspectrum sharing and the amount of new spectrum that may be made intouse. The use of small cells makes it easier to reuse a given frequencyfor geographically separated services, which increases the amount ofnetworks which may share new bandwidth during the times when theincumbent or the government allows for use by other services. Anothertechnical solution to facilitate sharing may be the utilization ofcognitive technologies, such as access to geo-location databases andsensing.

Effectively, mobile broadband services accessing shared bands may gainlocal or shorter term access to spectrum and may provide the sameservices as those services provided using exclusive spectrum licenses,but without the large costs associated with the purchases of long termexclusive licenses. Accordingly, the use of spectrum sharing may createopportunities for a new set of use cases.

In certain scenarios, there may be incumbent usages that may allowdeployment of not only small cells but also larger cells and/or longerterm licenses for shared use. This may depend on the nature anddeployments of the actual applications and on the frequency bands. Ingeneral, the concept of shared access to spectrum, which may effectivelymake a significant amount of new spectrum available, may enable newentrants to the market, including for example new network operators andvirtual network operators, thus increasing competition.

According to an example of shared use of spectrum, Restricted/LimitedAccess Networks (RLANs) may be deployed in the 5 GHz band, where DynamicFrequency Selection (DFS) and power control may be employed in order forRLANs to be able the share the band with radars. DFS may be a type ofsensing, which may allow RLANs to detect the channels that may be usedby the radars and choose channels that are available. Use of DFS mayallow RLANs to use the same bands as radars in a dynamic manner and notcause harmful interference to the radars, while avoiding harmfulinterference from the radars. Power control may help the RLANs tocoexist, even when originally there may be no coordination among them.

Use of Television White Space (TVWS) in the ultra-high frequency (UHF)broadcasting band is another example of shared use of spectrum. Certainportions of the spectrum for terrestrial broadcasting may not be usedfor TV transmissions, mainly due to broadcast network deployment issues.These unused portions of spectrum may be referred to as TVWS. TheFederal Communications Commission (FCC) has opened up these TVWSfrequencies for a variety of unlicensed uses and the Office ofCommunications (Ofcom) in the United Kingdom is in the process of doingthe same.

Many other administrations are also considering the use of TVWS. Thesefrequencies may be exploited in license exempt manners by secondaryusers for any radio communication given that such use may not interferewith other incumbents and/or primary users. As the amount and exactfrequencies of unused spectrum vary from location to location, specifictechnical solutions may be employed. Key technical solutions that may beused include, but are not limited to, geo-location of a device andaccess to a database that may instruct the device about the availablechannels in the location of the device and/or the maximum allowedtransmit power in that location.

The use of Wi-Fi, LTE and other cellular technologies within the TVWSbands has recently been considered, notably in standards bodies such asEuropean Telecommunications Standards Institute (ETSI) ReconfigurableRadio Systems (RRS), ETSI Broadband Radio Access Networks (BRAN), IEEE802.19, and Internet Engineering Task Force (IETF) Protocol to AccessWhite-Space (PAWS).

In existing solutions for TVWS, there may be no coordination among whitespace devices (WSDs), as there may only be mechanisms to protect theincumbents. Therefore, additional technical measures may be needed sothat the networks based on WSDs may provide QoS.

In contrast to unlicensed approaches to use bands in a shared manner,there is also a licensed approach to spectrum sharing, which in Europeis known as the Licensed Shared Access (LSA). The LSA may be based on atwo-tiered model, where Tier 1 users may include various incumbents(e.g. governments, defense, etc.), and Tier 2 users may include usersauthorized for exclusive use on a shared and binary basis, includingtime, location and/or frequency, with the incumbent.

FIG. 2 shows a comparison 200 of example spectrum use models, where theexample spectrum use models include a licensed approach 202, anunlicensed approach 204, and the LSA 206 complementary license model.The licensed approach 202 may include auctions of cleared spectrum, andmay result in exclusive use of spectrum with ensure QoS. The unlicensedapproach 204 may include, for example, Wi-Fi over 2.4 GHz, 5 GHz, or 60GHz, and may result in shared usage with unpredictable QoS.

According to the LSA approach 206 for providing shared exclusive usage,while the current incumbent usage may stay unaffected, the unusedportions of the band may be exclusively assigned to a secondary user,such as a mobile broadband operator, or in some cases to two or moreoperators. The LSA approach 206 may ensure QoS by providing exclusiveuse to secondary users on a shared and binary basis with the incumbent.If there are more than two LSA licensees, then they may not haveexclusive rights to the shared band, and some coordination may be neededbetween them in order to allow them to provide QoS dependent services.

The LSA framework itself may be technology and band neutral, but inpractice it may first be applied to make additional spectrum availablefor mobile broadband. For example, an initial band where the LSAapproach may be employed in Europe is 2300-2400 MHz. In n example, theLSA model may be a good match for Mobile Network Operators (MNOs), whomay get capacity enhancement when operating as Tier 2 users in sharedspectrum.

In the United States, a President's Council of Advisors on Science andTechnology (PCAST) report has proposed a hierarchical three-tier accessmodel to enable shared access to the federal spectrum, shown in FIG. 3.As shown in FIG. 3, Tier 1 users may be the incumbents or FederalPrimary Access users, may have guaranteed access, and may not excludespectrum from use if that spectrum isn't in current need. Tier 2 usersmay be Secondary Access users and may have a lower priority than Tier 1when accessing the spectrum. Tier 2 users may register with a databaseand pay a fee to get an individual license for spectrum use withpossible allowance provisions of QoS, and may be high power.

Tier 3 users may be General Authorized Access users and may have thelowest priority when accessing the spectrum. Tier 3 users may not payfees for using the spectrum, which they may use in an opportunisticmanner without QoS provisioning and may be low power users. For example,Tier 3 users may use sensing and/or a database to determine accessavailability.

A key feature of the three-tier model is that lower level use may not beallowed to cause harmful interference to higher level use. FIG. 4 showsa system diagram of a shared spectrum access system 400 with three tiersof access, in accordance with the PCAST report. A shared spectrummanager (SSM) 402 may coordinate access to the shared spectrum 404 amongthe different tiered users. According to one example, shared spectrumaccess may be employed in the 3550 to 3700 MHz band, which may be usedby radars, earth stations of the Fixed Satellite Service and WirelessInternet Service Providers.

Tier 1 users may include, for example, the military 406 and publicsafety and/or government services 408. Tier 2 users may include, forexample, Small Cell LTE or Wi-Fi networks 410. Small Cell or Wi-Finetworks 410 may send a spectrum request 415 to the SSM 402 to gainaccess to shared spectrum 404. Tier 3 users may include ad-hoc,consumer, and smart grid users 412.

Employing either the PCAST or the LSA model may facilitate QoSprovisioning for users sharing the spectrum with incumbents. Forexample, QoS provisioning may apply, but is not limited to Tier 2 usersin the PCAST model, and LSA licensees in the LSA model. The QoSprovisioning may be facilitated when only one or few users or operatorsmay get the license for the shared use.

QoS provisioning may be possible in cases where only a limited amount ofspectrum users and their spectrum use may be known. The amount ofaccessible spectrum to the Tier 2 user may be defined, and in case theamount varies over time, a prediction may be given to the Tier 2 user ofthe timely variance and an assurance of the minimum amount. In a knownradio environment, the Tier 2 user may be offered protection fromharmful interference. This in turn may allow the Tier 2 user to haveguaranteed access to spectrum in a manner that also allows theprovisioning of QoS, which are related to Quality of Access (QoA).

QoA may be defined such that the amount of spectrum made available tothese applications has to be sufficient over the required time and/orover the required geographical area and/or that the access may need tobe protected from harmful interference from other spectrum use.

Another quality related measure is Quality of Operation (QoO), which maydefine the quality metric influenced by the use of the shared spectrumor a specified portion of the shared spectrum. The term may refer to,but is not limited to: signal-to-noise ratio, capacity, throughput,frame or bit error rate, time of operation or spectral efficiencyobtained over the spectrum. The QoO of a user may reflect the usabilityof the spectrum used by that particular user.

Access to spectrum may be exclusive or shared. For example, in the caseof one Tier 2 user or one LSA licensee, it may have exclusive rights touse the portions of spectrum that may not be used by the incumbent. Forexample, in case of two or more Tier 2 users or LSA licensees, they mayneed to share the unused portions of the band. In that case, anarrangement or protocol may be needed to facilitate QoS provisioning.

The ability to provide QoS may be a very important aspect for mobilebroadband operators, as some of the services they offer haverequirements for certain QoS. This may have an impact on the value ofthe band and on the use cases and applications to be deployed.

Architecture and procedures may be developed for shared spectrum accessand/or for a shared spectrum manager (SSM). For example, a centralizedSSM may manage spectrum from a multitude of bands, coming fromincumbents (e.g. Tier 1 users), and made available for Tier 2 and Tier 3users. With some enhanced functionalities, the SSM may make spectrumavailable for Tier 2 Users in a manner that may provide QoSprovisioning. FIG. 5 shows a block diagram of an example shared spectrumsystem 500 for providing QoS and QoA to Tier 2 Users. The example sharedspectrum system 500 shows an SSM 502 and a Tier 2 User 504, and mayinclude other users and network entities that are not shown. The enduser 508 of the Tier 2 User 504 may communicate with the access network506, which may communicate with the SSM 502. The SSM 502 may provide theQuality of Access functionality. For example, the SSM 502 may makesufficient spectrum available and ensure interference protection fromother Tier 2 and/or Tier 3 Users.

The access network 506 may provision services to the end user 508, andmay provide QoS via QoS Mechanisms. For example, the access network 506may provide feedback to the SSM 502 on the QoA experienced by the Tier 2User 504, which may be for example based on measurements such as:average cell throughput, per cell average noise and interference level.

The end user 508 may provide feedback on QoS to the access networkentity 506, which may be for example based on measurements, including,but not limited to: signal to noise and interference ratio, noise orinterference level. The individual noise and interference measurementsprovided by the end users 508 may be averaged by the access networkentity 506 across all end users 508 that operate in that cell, togenerate the per cell average noise and interference level.

Shared spectrum use may be a major solution to the continuouslyincreasing spectrum shortage. It may allow a significant increase to theefficiency of overall spectrum use because currently unused portions ofspectrum may be taken into use by various wireless applications.However, technical, economical and regulator challenges may affect thepotential of shared spectrum.

Applications of shared spectrum use may be based on a primary-secondaryconfiguration. For example, the secondary use may include spectrum usein an unlicensed manner or by horizontal sharing where all use isunlicensed and there is no coordination among the users. For example,the use of Television White Space (TVWS) may be based on anon-interfering, no-protection approach. Such spectrum use may besuitable only for some applications. However, wireless applications thatmay require more spectrum, such as mobile broadband, may need to employmechanisms that allow provisioning of QoS and may put specificrequirements on their shared spectrum access, such as QoA.

Thus, technical spectrum management solutions may be needed withcapabilities for managing shared spectrum use in a dynamic multisystemenvironment while providing the required QoA.

In order to be able to provide QoA for Tier 1 and 2 users, the SSM mayneed to control the admission of the Tier 2 Users and Tier 3 User (whichmay be referred to as T2Us and T3Us) in a manner that some or alladditional access to the available bands is under its control. Theassignments may need to be done by the SSM based on the actualcharacteristics of the devices and the actual network deployments,facilitating protection of Tier 1 and Tier 2 users from harmfulinterference. Additionally, the assignments may be updated based onchanges in the requirements and radio environment, so that the QoA maybe maintained.

Mechanisms for the SSM may allow spectrum access for Tier 2 and Tier 3users and the provisioning of QoA for Tier 2 Users in a dynamic sharedspectrum environment while ensuring the sufficiency of spectrum for theTier 1 Users and their protection from harmful interference. The SSM mayuse those mechanisms in accordance with the possible policies issued bythe regulator. The SSM may assign the requested amount of the availablespectrum for the Tier 2 and Tier 3 users while also prioritizing theTier 2 use based on the technical characteristics and the protectioncriteria of a particular system, the amount of spectrum made availableby Tier 1 users, and the spectrum needs announced by Tier 2 and 3 users.The assignments may be updated automatically and optimized by the SSMduring their validity time if the spectrum requirements, radioenvironment or the policy may change.

The SSM mechanisms may contain specific QoA provisioning relatedfunctionalities on top of the spectrum request and assignment mechanismsas described above. The QoA may mean that the amount of spectrum madeavailable to Tier 2 Users has to be sufficient over the required timeand over the required geographical area and that the access MAY need tobe protected from harmful interference from other spectrum use.

QoA provisioning mechanisms for Tier 2 Users may include, but are notlimited to the following exemplary embodiments. According to anembodiment, admission control mechanisms for T2Us and T3Us may allow theSSM to have full control over the spectrum usage and the radioenvironment. According to another embodiment, admission controlmechanisms may include authorizations, registrations and spectrumassignments. According to another embodiment, an administrativeprocedure and interface may be used between the SSM and the regulator,and may include new authorization approaches. According to anotherembodiment, an admission control mechanism may be based on QoO levels ofT2Us.

According to another embodiment, mechanisms protect Tier 1 Users (T1Us)and T2Us from harmful interference from lower tiers. Protection of T1Usfrom harmful interference is a fundamental aspect of the shared spectrumuse concept. Protection mechanisms may assist in making unused portionsof T1U spectrum available for shared use while guaranteeing a QoA of theT1Us. Furthermore, protection of T2Us from harmful interference may beprovided as part of provisioning of QoA for the T2Us. According to anembodiment, use of time-varying protection contours and coveragecontours may be applied to a multitude of devices or device categories.According to another embodiment, the SSM may take into account otherapplications that operate in bands adjacent to those that the SSMmanages or in the adjacent geographical area(s), which may befacilitated by the administrative procedures.

According to another embodiment, mechanisms for individual spectrumassignments may be based on spectrum requests from T2Us and for spectrumreassignments based on, for example, changes in spectrum use, spectrumenvironment, and/or spectrum requirements. Spectrum assignmentmechanisms may be an important part of QoA provisioning to the T2Usbecause sufficiency of spectrum and interference free operation may beessential to T2Us. Spectrum assignment mechanisms may also facilitatemaintaining the QoA for T2Us in a changing radio environment.

According to another embodiment, a spectrum buffer may be used tofacilitate immediate assignments and reassignments. Buffer dimensioningmay be based on, for example, traffic predictions done by the SSM andmay use traffic and spectrum use reports from the users. According toanother embodiment, technology specific and/or time-varying protectioncontours and coverage contours may be used in determining the allowedlocations and coverage of Tier 2 and Tier 3 systems and/or users.According to a pixel based approach, radio quality maps may be createdfrom interference measurements and utilization in connection withinformation about a Tier 2 User's technologies and deployments. Thisapproach may allow prioritization of low interference channels andavoidance of channels with potentially harmful interference, for examplein determining the assignments for QoS critical services.

According to another embodiment, measurements of analogue front endadjacent channel leakage power may be used to identify interference andto facilitate suppression of interfering transmissions. According toanother embodiment, a QoA resolution process may be used by the SSM tosolve QoA events, comprising, but not limited to the following actions:reassignment, evacuation, and reimbursement. According to anotherembodiment, user category and/or band specific, time to live (TTL) basedcontrol signaling may manage the time aspect of spectrum assignments andreassignments. This approach may facilitate timely spectrum reclaim andagile reassignments. According to another embodiment, mechanisms maydeal with T1U spectrum reclaiming.

According to another embodiment, mechanisms may provide a limited degreeof QoA to T3Us. Mechanisms to facilitate some level of QoA for the T3Usmay include, but are not limited to, reserving a predetermined portionor a certain amount out of the spectrum made available by the T1U forshared use and assigning spectrum to the T3Us so that their assignmentsmay be spread evenly across the available spectrum. Mechanisms formulti-tiered shared spectrum access are described in further detailbelow.

A process may facilitate the provisioning of QoA in a dynamic sharedspectrum environment. The operation of the SSM may include, but is notlimited to, any of the following processes: an administrative procedure;registration of all involved users; spectrum offers; spectrum requestsand/or assignments; and/or spectrum reassignments. The QoA provision maybe taken into account in any or all of these processes, which aredescribed in further detail below.

According to an embodiment, an administrative procedure may be used. TheSSM may use information and guidance from a regulator, which may includean administrative phase for communication between the SSM and theregulator. This administrative phase may occur, for example, before theSSM starts its operation that manages shared spectrum to make itavailable and allow provisioning of QoA for priority users (e.g. T2Us).The administrative phase may provide the initial information that theSSM may use to establish its operation. Changes to information occurringduring the operation of the SSM may be updated by the regulator.

According to an embodiment, a T1U registration phase may includeregistering each T1U with the SSM. T1U registration may include, but isnot limited to, collecting information about the T1Us and theirtechnologies, including for example transmit and receivecharacteristics, technical deployment characteristics and protectioncriteria. Ensuring continuous protection of T1Us and allowing evolutionof T1U services over time may be used as prerequisites for making thespectrum unused by T1U available for other uses and users. If the T1U isnot protected from harmful interference, it may not be willing to makespectrum available for shared use. The SSM may update its technicaldatabase according to the received information. In an example, the T1Uregistration phase may be done in connection with a T1U spectrum offerphase, for example, the first T1U spectrum offer phase.

In case the T1U uses spectrum in a confidential or classified manner,the regulator may act as a proxy and deliver to the SSM informationabout the available spectrum and the associated restrictions on the useof that spectrum for lower tier users. In such a case, the T1U may notneed to register at the SSM.

According to another embodiment, a T1U spectrum offer phase may enableT1Us to inform the SSM about the spectrum that they may make availablefor lower tiers. The SSM may add the available bands and theircharacteristics to its database, for example.

FIG. 6 shows a signal flow diagram of an example procedure 600 includinga T2U registration phase 602, and a T2U spectrum request and assignmentphase 604 between at least one T2U 606 and an SSM 608. The T2U 606 maybe, for example, a device, AP, BS and/or operator. A T2U registrationphase 602 may include registering T2Us and collecting information aboutthe T2Us and their technologies including, but not limited to, transmitand receive characteristics, technical deployment characteristics, andprotection criteria. The T2U 606 may send a user and technologyregistration message 610 to the SSM 608. For example, the user andtechnology registration message 610 may include, but is not limited tofollowing information for the T2U 606: identity, device class and/orprotection criteria.

Protection of T2Us from harmful interference may be an important elementof the QoA provision. The SSM 608 may update its user and technologydatabase 612 according to the information received from the T2U 606.Unless there is no advance authorization from the regulator of the T2U,an individual authorization may be needed. Accordingly, the SSM 608 maycontact the regulator (not shown in FIG. 6) on behalf of the T2U 606 andmay apply for an individual authorization for the T2U 606, such that theSSM 608 may act with the permission of the regulator.

In an example, the SSM 608 may be authorized to issue the individualauthorizations on behalf of the regulator. In this case, the regulatormay have communicated the associated authorization criteria and othernecessary guidance for issuing the authorizations during theadministrative phase. The SSM 608 may send a confirm registrationmessage 614 to the T2U 606 to confirm registration, such that theconfirm registration message 614 may include, but is not limited to auser identification (ID). It may be noted that while some emergingstandards, like IETF PAWS, may include a registration phase, they maynot address the protection criteria. The T2U registration phase 602 maybe combined with the T2U spectrum request and assignment phase 604, asdescribed below.

The T2U spectrum request and assignment phase 604 may be initiated bythe T2U 606 by sending a spectrum request message 616 to requestspectrum from the SSM 608. The spectrum request message 616 may include,but is not limited to, any of the following information: an amount ofrequired channels and/or bandwidth, and information about the intendeddeployment, user ID, area and/or locations, and/or time. The QoA aspectmay be provided by the SSM 608 by way of an assignment 618 of sufficientspectrum for the T2U 606 and by ensuring protection of the T2U 606 fromharmful interference. For example, the SSM 608 may ensure that there isno harmful interference to the T2U 606 from T1Us, other T2Us, T3Us,and/or applications in adjacent bands (e.g. outside of frequenciesmanaged by the SSM 608) or in adjacent geographical locations.Furthermore, the SSM 608 may ensure that there is no harmfulinterference and/or operational limitations to T1Us.

The SSM 608 may send an assignment message 620, which may include, butis not limited, any of the following information regarding theassignment: usable channels, geographical location, area of operation,maximum allowable transmit power in the channel (P_(tx-max)/ch), and/orthe validity time of the assignment. The T2U 606 may send a confirmationmessage 622 to confirm used resources, indicating, for example, thechannels and/or transmit power P_(tx) for the user resources. Based onthe confirmation message 622, the SSM 608 may update its assignmentand/or protection database 624.

According to an embodiment, a T3U spectrum request and assignment phasemay be used for registration of the technology and deployment used byT3U(s). If a pixel based approach is in use, T3U spectrum request andassignment phase may include making transmit and deploymentcharacteristics (for example, including transmitter locations) availablefor the SSM, which may be needed to ensure the protection of T1Us andT2Us from harmful interference from the T3Us. In return, the SSM mayinform the T3U(s) regarding the locally available channels and/orallowed transmit powers. In an example, devices with pre-definedemission characteristics (e.g. predefined device categories) may beallowed to be used in certain frequencies in certain areas, such asinside a contour. Depending on the policy issued by the regulator, a T3Umay also be required to register individually. The T3U spectrum requestand assignment phase may be relevant to the TVWS assignment processdefined by the Conference of European Postal & Telecommunications (CEPT)or used in the United States.

According to an embodiment, a spectrum reassignment phase may be used inconnection with possible changes in spectrum requirements or radioenvironment so that a QoA may be maintained during a portion or thewhole duration of the assignment. According to an example scenario, aT1U may need some or all of its spectrum back for its own use, which maybe indicated by a T1U spectrum reclaim. In this case, spectrumreassignment may to be performed so that spectrum may be reassigned tothe T1U and, if possible, to the T2U.

According to an embodiment, an administrative phase and communicationmay be defined between the SSM and the regulator. The regulator maycomprise an automated and/or non-automated entity managed by theregulator, including, but not limited to, a database, active entity,human interface and/or secure website.

An administrative procedure may provide the SSM with essentialoperational information before the actual spectrum requests andassignments can take place. The administrative procedure phase may befor communication between the regulator and the SSM to authorize the SSMto communicate the relevant policies and possible information about theissued authorizations of the involved players. Depending on the policyof the regulator, the SSM may be authorized to issue individualauthorizations on behalf of the regulator to the users that requestaccess to spectrum, and in that case the SSM may need the authorizationcriteria from the regulator.

The SSM may also get information about the spectrum use within itsgeographical coverage area in bands adjacent to the bands that it maymanage and on the co-channel spectrum use adjacent to its geographicalcoverage. The SSM may store this information in its database(s). Theadministrative phase may be repeated periodically or on a need basis,for example if the policy or the use in the adjacent frequencies changesin line with the policy issued by the regulator. The administrativeprocedure may include the SSM reporting to the regulator about thespectrum management activities, spectrum usage, and interferenceincidents that may have taken place.

The policy obtained by the SSM from the regulator may contain a list ofT2Us and/or T3Us that are authorized to use the services of the SSM. Forexample, an operator may request the authorization to use sharedspectrum from the regulator in its country. If the request issuccessful, the regulator may allow the operator to have access toshared spectrum in a specific band, geographical region, and/or timeperiod. This authorization may then be indicated to the SSM within theadministrative procedure. When that specific operator makes a requestfor spectrum from the SSM, the SSM may then assign spectrum to theoperator based on the information obtained during the administrativeprocedure.

The policy received at the SSM from the regulator may also be used bythe SSM to prioritize the different T2Us and/or T3Us in terms ofspectrum to be assigned to each, or to define a maximum amount ofspectrum per T2U and/or T3U in situations where there is a scarcity ofspectrum.

FIG. 7 shows a signal flow diagram of an example administrativeprocedure 700 between an SSM 702 and a regulator 704. The administrativeprocedure 700 may include an administrative part 730, an administrativeupdate part 732, and an SSM reporting part 734.

As part of the administrative part 730, the SSM 702 may initialize andcontact the regulator 704 by sending a request for the administrativeinformation, 706. The regulator 704 may respond by sending a policymessage 708 that may indicate the applicable policy that contains theguidance for the SSM 702 and the overall approach for the assignmentsfor T2Us and/or T3Us. For example, the information in the policy message708 may include, but is not limited to: the priorities related to thedifferent users, how to make spectrum available for users in each tier,timing issues, and/or reclaim requirements.

The regulator 704 may send user authorization information 710 to the SSM702. For example, when the regulator 704 deals with the authorizationsof some or all users, it may communicate to the SSM 702 the issuedauthorizations thus far. In another example, the regulator 704 mayauthorize the SSM 702 to issue individual authorizations on its behalfto some or all of the users. Relevant authorization criteria may also beincluded in the authorization information 710.

The regulator 704 may also send to the SSM 702 spectrum usageinformation 712 that the SSM may need to perform its task. For example,the spectrum usage information 712 may include spectrum use in adjacentbands or adjacent geographical areas managed by the SSM 702 ornon-confidential incumbent spectrum use information. The spectrum usageinformation 712 may be complemented by or may include protectioncriteria of adjacent band and/or adjacent geographical area usage. TheSSM 702 may store the information received from the regulator 704 in auser and technology database(s) 714. The SSM 702 may send a confirmationmessage 716 to the regulator 704 to confirm the reception of theinformation and store it in its user and technology database. The SSM702 may start operation in accordance with the received information fromthe regulator 704.

As part of the administrative update part 732, the regulator 704 maysend to the SSM 702 an update of administrative information 718, whichmay include, but is not limited to, information related to the policy,issued authorizations, and/or relevant spectrum use. The SSM 702 maysend confirmation 722 of the reception of the information, and may storethe received information in its user and technology database 720. TheSSM 702 may continue to operate in accordance with the updated guidanceinformation from the regulator 704.

As part of the SSM reporting part 734, the SSM 702 may report activitiesand/or issued authorizations 724 to the regulator 704, includingreporting about the assignments, occurrences of interference, andspectrum utilization and/or efficiency in accordance with the policyprovided by the regulator 704. The reporting 724 by the SSM 702 may beperiodic. The regulator 704 may accordingly store updated information inits database 726 and may send confirmation 728 to the SSM 702.

According to an embodiment, T2U and T3U admission control methods may beused by which the users may be authorized by the regulator to usespectrum through the SSM, and by which the SSM may perform admissioncontrol when allowing new T2Us and/or T3Us to register and later obtainspectrum assignments.

Admission control may be an important part in ensuring that the radioenvironment is predictable and under the control of the SSM. Thepredictability may facilitate the avoidance of harmful interference. Theadmission control may be applied to T2Us and/or T3Us, and may include,but is not limited to, any of the following: authorizations,registrations, and/or spectrum assignments. The admission control maydepend on the policy issued by the regulator addressing the eligibilityof particular entities getting authorization to access spectrum by usingthe services of the SSM. The admission control may depend on theavailability of spectrum to fulfill the spectrum requirements of theT2U.

T3U admission control may depend on the authorization and/or sufficiencyof spectrum, but may also depend on operating conditions of T2U(s). Forexample, if a T2U is close to its QoO limit, then a new T3U may not beadmitted. Similarly, a T3U may be allowed if the nearby T2U isexperiencing acceptable QoO. Being close to the QoO limit may indicate,for example, that the capacity of the network is approaching the maximumthat can be accommodated into the assigned spectrum, and/or that theinterference level is increasing and approaching the maximum level.Admission control for T3Us for areas adjacent to affected T2Us isdescribed below.

Depending on the policy, individual authorization from the regulator mayallow use of the services of the SSM. This may apply to the T2Us. Forexample, certain Mobile Network Operators (MNOs) may be eligible to usethe services of the SSM if those MNO's would be individually authorizedby the regulator. In the case the T2U may have received an individualauthorization from the regulator before the registration to the SSM, itmay provide an authorization key (e.g. provided by the administration)to the SSM during the registration process as a proof of the validauthorization and inform the SSM about the time validity of theauthorization.

FIG. 8 shows a signal flow diagram of an example T2U registrationprocedure 800, where the SSM 804 may apply for individual authorizationwith the regulator 806 on behalf of the T2U 802. In a first example of aT2U registration process 830, T2U authorization from the administrationmay exist or may not be needed. Accordingly, the SSM 804 may receive auser and technology registration request 808 from the T2U 802 to collectinformation from the T2U 802 in order to be able to apply for theauthorization. The user and technology registration request 808 mayinclude, but is not limited to: the category and/or identity of the T2U,the technology to be deployed, a description of services to be provided,protection criteria, intended time frame of operation, and/or theoperational area (e.g. geographical coverage). The SSM 804 may updateits user and/or technology database 810, and may send a confirmregistration message 812 to the T2U 802.

In a second example of a T2U registration process 832, T2U authorizationfrom the administration may not exist but may be needed. In this case,the SSM 804 may apply for authorization for the T2U 802.

The SSM 804 may receive a user and technology registration request 814from the T2U 802 to collect information from the T2U 802 in order to beable to apply for the authorization. The user and technologyregistration request 814 may include, but is not limited to: thecategory and/or identity of the T2U, the technology to be deployed, adescription of services to be provided, protection criteria, a timeduration, device classes, and/or the operational area (e.g. geographicalcoverage). The SSM 804 may apply for the individual authorization forthe T2U 802 to the regulator 806 via an authorization request message816. The regulator 806 may process the authorization 818, and may send agrant message 820 to the SSM 804 to grant individual authorization tothe T2U 802. The SSM 804 may update its user and/or technology database822 accordingly, and may send a confirm registration and authorizationmessage 824 to the T2U 802.

According to an embodiment, an SSM may be authorized to issue individualauthorizations to the T2U on behalf of the regulator. In this case, theSSM may need the applicable criteria for issuing the authorizations,which may be delivered to the SSM as part of the administrative phase.Applicable criteria may be based on the nature of the applicant. Forexample, for a T2U being a licensed MNO, a hospital, or a universitydeploying a network, the criteria may include the geographical location,deployed technology and/or a combination of several criteria.

Some T2Us may not need an individual authorization, such that thesuccessful assignment by the SSM may be considered as the authorizationdepending on the policy. For example, the policy may allow use ofcertain technologies without individual authorizations.

The similar mechanisms as those described above may be used forauthorizing T3Us. However, T3Us may operate under general authorization,such that no individual authorization or license may be needed.Additionally, pre-defined criteria may need to be met.

The issuance of authorizations may include any of the followingapproaches. According to an approach, all users that have beenindividually authorized by the regulator may be allowed to register andmay be entitled to spectrum assignments. A mechanism such as anauthorization key may be employed for the authorized users to indicateto the SSM in a reliable manner that they have the requiredauthorization.

According to another approach, the SSM may be allowed to contact theregulator on behalf of the users, and may get the authorizations basedon the identity, spectrum requirements, and/or technical characteristicsof the users. Secure communication may be used for any or all of thecommunications between the SSM and the regulator. The regulator mayissue the individual authorizations, which may include the validity timeand/or possible operational conditions.

According to another approach, the SSM may be authorized by theregulator to authorize the users. For example, this may be done based onpredefined criteria in line with a policy from the regulator. In casethere is no need for individual authorizations, the SSM may allow anyuser to register and get assignments, or the SSM may choose the usersthat may get registered based on a policy issued by the regulator orother criteria. The individual authorization may be renewed when thecurrent authorization expires, or if there are technical, operationaland/or commercial changes that are specified in the policy.

According to an embodiment, the registration phase may allow theregistration of authorized T1Us, T2Us and T3Us and the main technicalcharacteristics of the technologies they employ. A unique user ID may beissued as part of the registration to each user by the SSM. The SSM mayinform the users about the validity times of the registrations.

For example, the validity time of the registrations may be defined inthe policy, or may be initially determined by the SSM. The registrationmay be renewed when its validity time expires, of in the event oftechnical, operational and/or commercial changes that may be specifiedin the policy.

According to an embodiment, the registration may be valid for a certainmaximum time, and may expire if the user may not make any spectrumavailable or request for any assignment during the validity time of theregistration. In this approach, the registration period may beautomatically extended due to the activity of the user. Registration ofcharacteristics of T3U technology may be used to ensure the protectionof the T1Us and T2Us, unless the T3Us are using a technology which maybe represented by generic characteristics for the protectioncalculations. This may be the case if, for example, a single technologyor few essentially similar technologies may be used by the T3Us, such asWiFi APs.

While a separate registration phase may be used, according to anotherapproach the registration and the initial spectrum offer and/or requestmay be performed in a single step. The amount of control traffic may bereduced if the technical characteristics are communicated within theregistration phase and not within the spectrum offers and/or requests.

The SSM may use the registration phase as part of the admission controland may accept registrations based on any of the following:authorizations, technical criteria, and/or operational criteria. Forexample, operation criteria may include advance spectrum requirementestimation, aiming to avoid overloading of the band. The SSM mayestimate the average available spectrum based on the number of T1Usregistered and some indication of the spectrum they are willing to give.The SSM may estimate the needed spectrum based on the number of T2Uscurrently registered. The SSM may also admit new T2Us only if there isno obvious risk that there will be a shortage of spectrum in the longrun.

According to an embodiment, a T2U may be automatically associated withsome limit of spectrum use that the T2U may be assigned by theregulator. Thus, when the T2U registers initially, the SSM mayautomatically associate some maximum amount of spectrum usage with thatuser based on what may be associated with in the policy. Such limitationmay be communicated to the T2U at the registration, and it may beimplemented within the assignments.

Mechanisms may protect the higher tier users from harmful interferencefrom lower tier users, as described below. According to an embodiment,an enhanced contour based approach may be used. An enhanced contourbased mechanism may protect the T1U from harmful interference from T2Usand T3Us and may protect a T2U from harmful interference from the T1U,other T2Us and T3Us. Protection may also be extended to the T3U fromharmful interference.

The T1U protection contours may define the area dedicated for theoperation of the T1U, surrounded by a protection zone, where thetransmitters and receivers of T2U (with known technical characteristics)may not enter in order to avoid causing harmful interference to the T1Uor receiving it from the T1U. The combined T1U/T2U protection contoursmay define the combined area dedicated for the operation of the T1U andT2U, including the protection zone, where the transmitters of T3U (withknown transmit characteristics) may not enter in order to avoid creationof harmful interference to T1U and T2U. The contour may not have to be aprotection contour (e.g. area where T3U may not enter), but it may be acoverage contour, an area where the transmitters of T3U may operate.

The contours may be calculated by the SSM based on the technical and/ordeployment information on the protected use and on the “entering” use.The SSM may take into account the possible radio environment qualityinformation collected from T2Us based on measurements and sensing. Thecontours may be used by the SSM in defining the T2U assignmentsindividually or communicated to the T3U as a contour in response to aspectrum request. For example, the SSM may use the contour approach indefining the available spectrum and operational conditions for a T2U andcommunicate the remaining spectrum and its operational area for theT3Us. Such contours may be calculated taking into account the actualtechnical characteristics and deployment conditions of the concernedsystems.

As the T1U spectrum use may be more or less time varying, the contoursmay be used in a time varying manner, and may be updated in a timelymanner to reflect the changes in spectrum use, deployments, and/ortechnology characteristics. For this mechanism to be used, the SSM mayneed to define the validity time of the contours, and the usersutilizing spectrum based on such contours may have to check the SSM ifupdated contours are available before the expiry. As the protected areamay be different for different channels (e.g. sub-bands), separatecontours may be defined for each of channel by the SSM.

FIG. 9A shows a system diagram of an example of a shared spectrum accesssystem 900 with three tiers of access and protection contours. As shownin FIG. 9A, T1U 902 has a T1U protection contour 904, in which T2U 906and T3U 910 may not operate. Similarly, T2U 906 has a protection contour908 to protect it from harmful interference from other T2Us and lowertier users (e.g. T3Us). The coverage contour 912 for T3U 910 shows thearea around T3U 910 where T3Us may operate. Note that the size and shapeof protection contours may depend on many factors, including but notlimited to: time, technology (e.g. LTE, WiFi), deploymentcharacteristics (e.g. transmission power), topographical terraininformation, and the specific channel.

FIGS. 9B and 9C show signal flow diagrams of example T2U and T3Uassignment procedures 922 and 952, respectively, using protectioncontours. The example assignment procedures 922 and 952 in FIGS. 9B and9C involve T3U 912, T2U 914, SSM 916 and T1U 918.

According to the T2U assignment procedure 922 in FIG. 9B, followingregistrations 920, T1U 918 may send a spectrum offer 924 to the SSM 916,which may then define protection contours, 926, for T2U 914. Theseprotection contours may be defined for each technology and/or sub-band.The T2U 914 may send a T2U spectrum request, 928, to the SSM 916, whichmay define assignments and operation conditions, 930, for the T2U 914.SSM 916 may send message 932 to the T2U 914 including the assignmentsand operation conditions, and the T2U 914 may send a confirmationmessage 934. The assignments may have a validity time or time-to-live(TTL), 925. The SSM 916 may update protection contours 936 for T2U 914on an as-needed or periodic basis.

At any time, the T1U 918 may send an updated spectrum offer 938 to theSSM 916, which may accordingly update protection contours, 940, for T2U914. By the expiration of the TTL 925, the T2U 914 may send a TTL orspectrum assignment renewal request, 942, to the SSM 916, which mayreply with an updated assignments and operating conditions message, 944.The T2U 914 may send a confirmation message 946 back to the SSM 916.

According to the T3U assignment procedure 952 in FIG. 9C, followingregistrations 950, T1U 918 may send a spectrum offer 954 to the SSM 916,which may then define protection contours, 956, for T2U 914. Theseprotection contours may be defined for each technology and/or sub-band.The T2U 914 may send T2U spectrum requests, assignments and/or contourupdates, 958, to the SSM 916, which may define coverage contours forT3Us, 960, such as T3U 912.

The T3U 912 may send a T3U spectrum request message 962 to the SSM 916,which may respond with message 964 including the allowed coveragecontour and/or TTL for T3U 912. The allowed cover contour may have avalidity time or TTL, 955. At any time, the T1U 918 may send an updatedspectrum offer 966 to the SSM 916, which may accordingly updateprotection and/or coverage contours, 968. By the expiration of the TTL955, the T3U 912 may send a TTL expiry message, 970, to the SSM 916,which may reply with a coverage contour and/or TTL, 972, for T3U 912.

The protection contour approach may facilitate QoA for T1Us and T2Us. Byadding the time variance and taking into account the actual devicecharacteristics, the overall efficiency of such shared spectrum use maybe much higher than in other TVWS approaches. Furthermore, in the casein which the contours are used, the algorithms may be simpler than inthe case that each transmitter and receiver may be considered at theirlocations as is the case with pixel based approaches.

According to an embodiment, radio quality maps may be maintained at theSSM. A pixel-based geometry may allow definition of transmission powerfor individual transmitters and protection of individual receivers fromharmful interference in a time variant radio environment. The SSM maytake into account the technical and deployment characteristics of theusers, complemented by results of measurements conducted by the users.Such a location based approach may ensure protection of T1Us and T2Usfrom harmful interference while maximizing the allowed transmissionpowers. A pixel based approach may be defined for the TVWS use in Europeto protect terrestrial broadcasting and possibly wireless microphones insome countries. However, protection and coordination among the WhiteSpace Devices (WSDs) to avoid mutual interference may be lacking. WSDsmay not send measurement results about the radio environment to theGeolocation Database (GLDB). Alternatively, the GLDB may be used withWSDs employing the TVWS, and the SSM may assign spectrum individually tothe T2Us employing the unused portions of the spectrum of the T1Us toavoid causing harmful interference to each other. User protection fromharmful interference may take into account the actual interferencesituation.

According to an embodiment, measurements performed by users may becombined with the pixel based assignment approach by the SSM. Forexample, the users may measure the noise level in different pixels, andthe SSM may collect and combine them into a radio quality map. The mapmay be used when the SSM assigns spectrum to users that require the QoAand may take into account other factors including, but not limited to:the possible transmit powers, required signal-to-noise ratios, and/ordeployment. According to another embodiment, a master device of a T2Usystem may send periodic measurement results to the SSM that reflect thenoise levels as experienced by the T2U across its network coverage.Examples of master devices include, but or not limited to a small celleNB for an LTE based system, or an AP for a Wi-Fi based system.

According to another embodiment, QoO maps may be maintained at the SSM.Measurements may be applied to QoO maps. For example, a master device ofa T2U system may send periodic measurements to the SSM that reflect theeffective QoO as experienced by the T2U. The SSM may maintain a map ofthe effective QoO for any or all T2Us with active frequency assignmentssuch that the map may be associated with the protection contours or thepixel based approach. The QoO maps may be categorized based on theeffective QoO.

For example, different colors such as red, yellow and green mayrepresent different categories of QoO level. If the effective QoOreported by a T2U is below the minimum QoO target for that user, thenthe target QoS and/or QoO is not being met. In this case, thecorresponding coverage contour may be assigned the “red” color. When theeffective QoO is above the minimum target, but less than x % above theminimum target, the corresponding contour may be assigned the “yellow”color. When the effective QoO is more than x % above the minimum target,the corresponding contour may be assigned the “green” color. The mapcoloring scheme may be used in conjunction with the admission control,and/or the time to live (TTL) signaling as described below, in order tocontrol the QoO of T2U.

The SSM may maintain a QoO Map based on the periodic measurement reportsfrom T2U master devices (MDs). Examples of MDs include a small cell eNBin the case of LTe and an AP in the case of Wi-Fi. When the T3U isoperating adjacent to a T2U with QoO close to the minimum requiredlevel, the SSM may not assign and/or may not renew TTL spectrum to T3U.When the adjacent T2U's QoO is in the green zone (e.g. it meets requiredQoO with some margin above the minimum), the T3U may be assignedspectrum and/or its TTL may be renewed. When the SSM assigns spectrum toa T3U and the QoO of the adjacent T2U falls below a threshold, the T2Umay report a QoA event. Consequently, the SSM may use first in, firstout (FIFO) or last in, first out (LIFO) to deny TTL renewal to T3Us inthe area. The SSM may not renew TTLs for T3Us in the areas adjacent toaffected T2U.

According to an example procedure of a QoA event related tomeasurements, the SSM may assign spectrum for the T2U based on itsrequest and success in the auction (if in use). The assignment mayfulfill the QoA needed by the T2U if the assigned spectrum is sufficientand protected from harmful interference.

The T2U may start operation in the assigned spectrum and may monitor itsown QoO by measuring the channel performance and/or monitoring thequality of the assigned spectrum. The T2U may send the QoO measurementresults periodically to the SSM. The T2U may send the QoO measurementresults based on triggers. In case QoO degradation may be detected inthe assigned spectrum in use, the T2U may send a QoA Event message tothe SSM. The SSM may reassign spectrum for the T2U. This may involvechanges in the spectrum use of other T2Us and/or T3Us, and thereassignment may take into account measurements from other users.

When the QoA event is due to interference from a T3U to a T2U, the SSMmay perform admission control for the T3U for areas adjacent to theaffected T2U. In this case, the SSM may maintain a QoO map based on theperiodic measurement reports from T2U MDs. When the T3U is adjacent tothe T2U with yellow QoO, the SSM may not assign spectrum and/or renewthe TTL to the T3U. When the adjacent T2U is green and meets requiredQoO within a margin, the T3U may be assigned spectrum and/or have itsTTL renewed. When the SSM assigns spectrum to a T3U, then an adjacentT2U MD may report a QoA event and may use FIFO or LIFO to deny TTLrenewal to T3Us in the area. The SSM may perform no TTL renewal for T3Uin areas adjacent to affected T2U.

According to an embodiment, a channel management function (CMF)enhancement may be used for QoA event detection. CMF may comprise asoftware entity residing in an AP that may perform functions including,but not limited to, managing, selecting channels, and/or monitoringchannel status. A CMF may also make requests to the SSM for spectrum.

FIG. 10 shows a flow diagram of an example QoA event detection procedure1000. The QoA event detection procedure 1000 may be performed by a WiFiAP, for example. A WiFi AP may periodically measure QoO metrics onactive channels, 1002. Such measurements may include, but are notlimited to, the per WTRU received signal strength indication (RSSI), thetransmission rate (TxRate), medium access delay, and/or sensing ofalternate channels such as with a sensing toolbox. The AP may calculatean expected QoO based on its noise measurements, 1004. When theperformance of the link falls below an expected QoO, 1004, the WTRU maytrigger some extended measurements to evaluate the QoA, 1006. Otherwise,the AP may return to periodic measurements of QoO, 1002. When a QoAevent is confirmed, 1008, the AP may send a QoA report or event messageto the SSM, 1010. Otherwise, the AP may return to periodic measurementsof QoO, 1002.

According to another embodiment, leakage power may be measured. The useof measurements on leakage power into the analog front end of a T2U maybe used to indicate a problematic assignment by the SSM. For example,when a transmitter and a receiver communicate on one channel, there maybe a leakage signal from adjacent channel(s) into the active channel.When a WTRU or station has adjacent channel leakage power constantlyhigher than its Clear Channel Assessment (CCA) threshold, the CCAprocess may always assess its active channel as busy. That station maynot send out data and may always stay in back off status. When a T2U isfalling into this situation, it may perform a sensing procedure tospecify the adjacent channel leakage power and detect the sourceleakages into its analog front-end.

When an AP or WTRU always senses its active channel as busy and the APcannot send out or receive any data from WTRU, the AP may startperforming sensing over its active channel. If the AP experiencesinterference higher than the CCA threshold without receiving any datafrom the WTRU, it may assume there is interference leakage from theadjacent channel(s). That may be concluded because during a silencingperiod of the AP's basic service set (BSS) over the active channel theremay be no data coming in and or moving out from the AP and all BSSs maybe on back off status.

Sensing on the adjacent channels (on both sides of the active channel)may be used to try to determine some correlation between the power inthe adjacent channel and the leakage into the active channel. AP or WTRUmay deploy a suitable filter to tune to the left side adjacent channeland/or right side adjacent channel and may measure the signal powerreceived per each channel. The measurement on the active channel duringthe BSS silencing period may indicate the leakage interference power.The adjacent channel, which may have the signal power with the samecorrelation with signal power measured at the active channel, may be thecause of the issue. Furthermore, it may be possible to detect thetechnology used in the interfering transmissions.

FIG. 11 shows a frequency diagram of an example use of a band passfilter to detect the cause of adjacent channel leakage. Sensing isperformed along the adjacent and active channel frequencies to detectleakage. In the example scenario of FIG. 11, the right side adjacentchannel may be detected as the cause of the adjacent channel leakage,which may occur at WTRU X.

To improve the accuracy of the detection, WTRU X may deploy two separatechannel leakage measurements over its active channel: left sidemeasurement and right side measurement. The filter may be configured tonarrow down to half of the channel bandwidth. The measurements may findout the leakage signal power at the left side and at the right side ofthe active channel. The AP or WTRU then may compare these measurementswith the received signal power at the left side adjacent channel andright side adjacent channel. The cause of adjacent channel leakage maybe from the side with higher leakage signal power at the active channel,and this leakage signal power may have the same correlation with signalreception at the adjacent channel on the same side. This approach mayalso detect the scenario when adjacent channel leakage is coming fromboth sides.

According to another embodiment, when the AP or WTRU detects theadjacent channel leakage, the AP may report it to the SSM as a leakageevent. The SSM may send a request to the WTRU and/or AP that operate onthe adjacent channels in the same geographical area to schedule asilencing gap and send the results back to the SSM. By analyzing thecorrelation between the signal power at the active channel and adjacentchannel, AP X during the silencing gap duration may find the cause ofthe leakage and report it to SSM to solve the issue. The SSM may sendthe request to the system operating on the adjacent channel to lower itstransmit power level to avoid the leakage of harmful interference or theSSM may reassign the BSS operating on to active channel to a differentchannel with higher quality, for example.

According to an embodiment, a QoA event resolution procedure may be usedby the SSM to resolve a QoA event. FIG. 12 shows a system diagram of anexample QoA event resolution procedure 1200. The QoA event resolutionprocedure 1200 occurs between user 1202, interfering user 1204, and theSSM 1206. Interference 1208 caused by user 1204 toward user 1202triggers user 1202 to send a QoA event message 1210 to the SSM 1206,which in turn triggers a QoA decision 1212 at the SSM 1205 andresolution procedures 1214 between users 1202, 1204 and the SSM 1206.

When an SSM receives a QoA event from a user, it may be responsible toresolve the QoA issue. The SSM may have an algorithm to decide betweenany of the following actions: assign a new channel, or evacuateinterfering users. According to the former action, the SSM may assign anew channel to the user who issued the QoA event. The SSM may check thespectrum usage database and find a new channel that can provide therequired level of QoA to the user.

According to the latter, action the SSM may evacuate nearby users of thespectrum to resolve the interference to the user who issued the QoAevent. The SSM may send an evacuation message to the interfering user tovacate some channels. An interfering user may send a confirmation thatit has vacated the channel(s). If the interfering user fails to send aconfirmation message, then the SSM may assign a new channel to the userthat issued the QoA event, deny a renewal request for another user,and/or issue a reimbursement to the user that issued the QoA event.

If the evacuation did not resolve the QoA issue, then the user thatissued the QoA event may send another QoA event message indicating thatthe problem was not solved. The SSM may then further evacuate channelsof nearby users until the QoA issue is resolved. If after a number ofattempts the SSM fails to resolve the QoA issue then the SSM may issue areimbursement.

To determine if a user is nearby, the SSM may search the usage databasefor any users operating within a radius R who may be operating on thesame band as the Tier 2 user who sent the QoA event. For example, thisradius may be a function of the maximum power level allowed on thechannel, the propagation characteristics of the frequency, and/ortransmit power mask. According to another embodiment for evacuating auser, the SSM may issue a shortage of spectrum notice which may includea reimbursement as per the QoA agreement.

According to an embodiment, control signaling may be used to manage thetime aspect of spectrum assignments. The concept of TTL may be used toallow for time-limits and renewals to spectrum reservations, and toallow the database to contact the secondary device and immediatelyrescind its authorization to use the spectrum. This implies that the TTLmay be used to ensure the time validity of the protection of theincumbent users (e.g. T1U) from harmful interference from the lower tierusers.

The TTL concept may be extended so that TTL signaling may be used by theT3Us, and TTL signaling may be used in connection with evacuationsignals to T2Us in the case the spectrum has to be released. Proceduresmay be used by the SSM in conjunction with the TTL concept used by a T3Uto maintain the required QoA of T2Us in case reassignments may beneeded.

The TTL may be set depending on the type of spectrum being shared and/oron the type of user sharing the spectrum. The TTLs of the T3Us may needto be relatively short to facilitate fast response to spectrumreassignments, whereas the T2Us that require QoA and may benefit fromlonger TTL in certain cases. The TTLs may be the same or different amongthe T3Us and the same or different among the T2Us, and may depend on thesource of the spectrum, for example on the T1U and the nature of itsspectrum use. Some spectrum may have a longer TTL because the advancenotice with which the T1U may need the spectrum back can be longer.

A framework for TTL timers and signaling is described below. According a“heartbeat” approach, the SSM may periodically send a TTL renewal signalif the spectrum use can continue. According to another approach, theuser may contact the SSM to ask for a TTL renewal.

According to an embodiment, a TTL renewal procedure is such that the TTLrenewal signal acts as a heartbeat for T2Us and/or T3Us. FIG. 13 shows asignal flow diagram of an example TTL renewal procedure 1300 for aT2U/T3U 1304 in communication with an SSM 1302.

The SSM 1302 may send a frequency assignment message 1306 to the T2U/T3U1304, such that the frequency assignment message 1306 may contain theTTL to limit the amount of signaling associated with TTL.

Once the T2U/T3U 1304 confirms the used resources via message 1308 andthe frequency assignment becomes effective, the SSM 1302 and the T2U/T3U1304 may start TTL timers 1310 and 1312, respectively. Prior to theexpiration of the TTL timer for a given T2U/T3U 1304, the SSM 1302 mayperform the following actions.

At some delta of time prior to the TTL timer expiry, the SSM 1302 mayevaluate if the TTL may be renewed, 1314, for the T2U/T3U 1304. Forexample, for a Tier 2 User, the SSM 1302 may check if the rental/leasetime of the channel has expired, or if the Tier 1 user may reclaim thespectrum. When the SSM determines that the TTL of the user may berenewed, it may send a TTL renewal message 1316 to T2U/T3U 1304. The SSM1302 and/or the T2U/T3U 1304 may restart the TTL timer 1317 and 1318,respectively, associated with the T2U/T3U 1304.

Once a T2U/T3U 1304 receives the TTL renewal message 1316, it maycontinue operating on the channel, 1320. For example, the T2U/T3U 1304may operate for the same TTL duration or until an evacuation command ifsuch message is received from the SSM 1302 before the TTL expiry.

FIG. 14 shows a signal flow diagram of an example TTL renewal procedure1400 for a T2U/T3U 1404 in communication with an SSM 1402.

The SSM 1402 may send a frequency assignment message 1406 to the T2U/T3U1404, such that the frequency assignment message 1406 may contain theTTL to limit the amount of signaling associated with TTL. Once theT2U/T3U 1404 confirms the used resources via message 1408 and thefrequency assignment becomes effective, the SSM 1402 and the T2U/T3U1404 may start TTL timers 1410 and 1412, respectively. Prior to theexpiration of the TTL timer for a given T2U/T3U 1404, the SSM 1402 mayperform the following actions.

At some delta of time prior to the TTL timer expiry, the SSM 1402 mayevaluate if the TTL may be renewed, 1414, for the T2U/T3U 1404. In thisexample, for a T3U 1404, the SSM 1402 may determine that the TTL cannotbe renewed. This may happen, for example, when the frequency assignmentalgorithm running at the SSM 1402 determines that the T3U 1404 generatesharmful interference to either protected T1 users, or to T2 users. Inthis case, the SSM may not send the TTL renewal signal to the T3U 1404.

When the T2U/T3U 1404 does not receive the TTL renewal signal from theSSM 1402 within a certain window from the TTL timer expiration, theT2U/T3U 1404 may cease any transmission and stop operating on thechannel, 1418, and may start evacuation procedures. The T2U/T3U 1404 maysend the an channel evacuation confirmation message 1416 to the SSM1402, which may include the cause of evacuation such as TTL timerexpired, or no TTL renewal message received, for example. Upon receivingthe evacuation confirmation message 1416, the SSM 1402 may update thefrequency usage database, 1420.

FIG. 15 shows a timing diagram of an example TTL renewal procedure 1500with a missing evacuation confirmation. At time 0, the SSM and T3U maystart their TTL timers, 1502 and 1504, respectively. At some timeTTL-delta prior to the expiry of TTL, the SSM may evaluate the TTLrenewal, 1506. At time TTL, the T3U has not received a TTL renewal,1508, and therefore may start an evacuation procedure, however, theevacuation confirmation may not be received at the SSM, 1510. In thiscase, at time TTL+gamma the SSM may determine that no evacuationconfirmation was received, 1512, and may send an evacuation command,1514, to the T3U that may in turn confirm the evacuation, 1516. The SSMmay update the frequency database accordingly, 1518.

FIG. 16 shows a timing diagram of another example TTL renewal procedure1600 with a missing evacuation confirmation. At time 0, the SSM and T3Umay start their TTL timers, 1602 and 1604, respectively. At some timeTTL-delta prior to the expiry of TTL, the SSM may evaluate the TTLrenewal, 1606. At time TTL, the T3U has not received a TTL renewal,1608, and therefore may start an evacuation procedure, however, theevacuation confirmation may not be received at the SSM, 1610. In thiscase, at time TTL+gamma the SSM may determine that no evacuationconfirmation was received, 1612, and may send an evacuation command,1614, to the T3U that may in turn unsuccessfully attempt to confirm theevacuation, 1616. As a result, the SSM may take additional evacuationmeasures, 1618.

The TTL timer values may be signaled from the SSM to the T2U/T3U uponthe frequency assignment. The values assigned to the TTL may depend onthe type of spectrum and its usage by the T1U to enable evacuation ofthe channel within the time requirements imposed by the T1U that offersthe spectrum for sharing.

For a given type of spectrum, the TTL associated with a T2U may belarger than the TTL associated with a T3U that may operate in the samefrequency. By increasing the TTL of T2U, the signaling overhead for theTTL renew messages may be reduced. At the same time, a lower TTL for T3Umay enable the SSM to control the usage of the channel in such a waythat QoA may be provisioned for T2U, especially in cases where changesmay be needed on a short notice for the assignments.

According to an embodiment, depending on the issued policy, the parts ofspectrum that are left unused by the T2Us may be assigned to T3Us in ashared manner. According to example, T3Us may be allowed to use theirspectrum in a shared manner without protection or coordination. They mayensure that there is no harmful interference towards the users in thehigher tiers. T3Us may also use the spectrum for free.

The SSM may reserve a certain minimum bandwidth (e.g. 5 MHz or 25 MHz)for T3Us. This bandwidth may not be used as a buffer to accommodate theincreased or changing T2U traffic, but may be available at any time forT3Us. This may ensure that there is always some bandwidth available forT3Us, regardless of the spectrum requirements of the T1Us and T2Us. Insuch a case, T3Us may be required to pay a fee for having guaranteedspectrum available, even though the spectrum use of the T3Us may not becoordinated or provided protection from harmful interference.

According to an embodiment, the SSM may coordinate the spectrum use ofthe T3Us, for example by spreading them evenly across the spectrum thatis made available for them, and thus spreading also the possibleinterference evenly among the T3Us. This type of approach may facilitateprovisioning of some QoA for the T3Us.

According to an embodiment, a T2U's spectrum requirements may change.The overall spectrum demand of the T2Us may change over time, forexample the T2U may need more or less spectrum in certain locations,areas, or over the whole deployed network. The T2U spectrum demand mayalso change during the T2U assignment. Depending on the policy, the SSMmay react and/or do reassignments.

FIG. 17 shows an example 3-tiered spectrum model in a location where atier 1 user (T1U) makes a certain amount of spectrum available for lowerlayers. As shown in FIG. 17, a change in the overall spectrum of the T2Uoccurs at time t₁, such that the T2U needs more spectrum. This changemay cause a reduction in the spectrum of the T3U by the same amount,assuming that the spectrum for T3Us may be used as buffer for changes.At time t₂, the incumbent T1U may need some bandwidth (BW) back, whichmay come out of the bandwidth available for use by the T2U and/or theT3U. At time t₃, the incumbent T1U frees up some spectrum, and makes itavailable to the T2U and/or the T3U.

According to an embodiment, to support changes in the needs of T2Uspectrum, a T2U may send a reassignment request to the SSM. FIG. 18shows a signal flow diagram of an example reassignment request procedure1800, involving a T3U 1802, a T2U 1803 and an SSM 1806. T2 and T3spectrum requests and assignments, 1808, may occur between the T3U 1802,the T2U 1803 and the SSM 1806.

The T2U 1804 may send spectrum reassignment request 1808 to the SSM1806, which may contain information including, but not limited to thefollowing: the reason for the request, details of how much more/lessspectrum is needed, the relevant geographical coverage, and/or therequired time duration of the additional spectrum.

In case additional spectrum may be needed by the T2U, the SSM mayperform a reassignment and/or optimization procedure, 1812, to check theavailability of suitable additional spectrum. If the T3U spectrum may beused as a buffer, and it may be fully utilized, the required amount maybe released from T3U use either by not renewing at least one TTL (e.g.N×TTL, where N≧1), 1815, or if the TTL is too long by sending anevacuation command to some of the T3Us (not shown). In an example notshown, the SSM 1806 may perform the optimization of all assignments atthe same time, and then the SSM 1806 may inform all affected users aboutchanged assignments.

In case of less spectrum is needed by the T2U 1804, the SSM 1806 maymake the released spectrum available for new use and may definereassignments, 1812, possibly associated with optimization that may takeinto account the release of spectrum. The portion of spectrum that maybecome available may be made available to the T2U 1804 (and/or the T3U1802) via a reassignment message, 1816, which may be confirmed by theT2U 1804 via a confirmation message 1818. The optimization may be doneimmediately or in line with the regular periodicity.

In a further example, if incentive auctions have been used the SSM maysend revised assignments and the reimbursement information to the T2Uthat released some of its spectrum. It may also be possible that the SSMdoes the optimization of the all assignments at the same time, and thenall relevant (changed) assignments may be told to the users by the SSM.If incentive auctions are used, and they would end up in awarding therequested additional spectrum to the T2U which requested more spectrum,or if other pricing mechanisms may be in use, the SSM may send revisedassignments and/or billing information to a T2U.

According to an embodiment, congestion predictions apply to scenarioswhere there may not be enough spectrum to accommodate the offeredtraffic. This may occur in any of the following example situations. Forexample, the spectrum requirements from T2U and T3U may increase untilthe capacity made available from the T1U may not enough to accommodatethe demand. In another example, the T1U may want back some or the entirespectrum it has made available through the SSM and the SSM may haveassigned it to other use. In another example, the T2U may need morespectrum and the SSM may have assigned all spectrum for T2U and T3U use.

According to an embodiment, congestion may be reduced or avoided byemploying predictions to be done by the SSM based on analysis of pasttraffic amounts and traffic patterns. The SSM may collect informationfrom the T2Us on the timely variance of the traffic demand over a timeperiod, such as a day or a week, for example. By using the knowledge ofthe traffic patterns, the SSM may manage the spectrum to maximize theefficiency of the overall spectrum use and ensure that the T2Us has QoAduring their assignments, even if there will be changes in the spectrumrequirements or radio environment.

The SSM may collect information about the past traffic and its trend andchanges over a time period such as a day or a week, for example. The SSMmay use this information to make traffic predictions to help ensure thatthere is enough spectrum regardless of timely variance for the usersthat require QoA. The SSM may use the collected information to maintaina spectrum buffer that helps in assigning additional spectrum when morecapacity is needed by a T2U.

Spectrum in such a buffer may be made available for use under theassumption that the users may need to be evacuated in case the spectrumin the buffer is needed for T2Us. Examples of events that may causebuffer evacuation include harmful interference emerging causing a needfor reassignment, new spectrum requests that ask for relatively wide newbandwidth, and mission critical applications that need spectrum veryrapidly.

In general, the use of a buffer may increase the assignment flexibilityof the SSM. For example, tier 3 spectrum may serve as such buffer, orspecific buffer spectrum may be reserved by the SSM. The use of a buffermay also be a topic for a policy issued by the administration (e.g. aregulator).

FIG. 19 shows a signal flow diagram of an example T2U trafficinformation collection procedure 1900 for prediction to be used inbuffer dimensioning. During a reporting period 1915, the T2U 1904 mayperiodically collect traffic information, 1908 and 1914, and sendperiodic traffic reports, 1910 and 1916, to the SSM 1906. The SSM 1906may build and add to a traffic pattern database, 1912 and 1918, based onthe received traffic reports 1910 and 1916. Based on the trafficpatterns, the SSM 1906 may dimension a buffer for sudden changes inspectrum needed by higher users, 1920. The SSM 1906 may then assignspectrum to the T2U 1904 and the T3U 1902 based on spectrum requests,and may reserve spectrum for the buffer, 1922.

According to an example, predictions may be used to set an upper limitfor the amount of spectrum assigned to users. For example, a spectrumlimit may be set per user category (e.g. enterprise WiFi user, or LTEoperator) or per individual user. The spectrum limit may facilitatesufficient capacity for a certain percentage of time, for example for95% of the time. Deriving such a limit may allow the SSM to manage itsspectrum in accordance with the policy related to fairness in spectrumassignments. The spectrum limit may be determined based on collectinginformation about the past spectrum use, including the variance over thetime, and taking into account the amount that the T1U has made availablefor lower tiers.

According to an embodiment, spectrum may be reclaimed by a T1U. Unlessthe portions of spectrum that are left unused by the T1U remain unusedpermanently, for example due to technical or operational reasons of theT1U, there may be instances where the T1U may need back portions of orthe whole spectrum it has made available for other use through the SSM.

According to an approach, the T1U may use spectrum occasionally or in aperiodic manner. The periodicity may be constant or varying over time.If the T1U need for spectrum is periodic, the SSM may accordinglyrelease the spectrum periodically back to the T1U. If the timing of theperiodicity is known beforehand (e.g at the time of the spectrum offer),the SSM may take the periodicity into account when it assigns spectrumfor T2Us and T3Us. The TTLs values of the assignments to T2Us and/orT3Us may be determined so that the spectrum becomes automaticallyavailable to the T1U when needed. This may assume that the TTLs are notrenewed.

According to another approach, the SSM may define the assignmentduration in an exact manner. According to either approach, there may beno need for a spectrum reclaim or evacuation commands from the SSM. Incase the T1Us use spectrum occasionally, and those occasions are knownwell beforehand, the SSM may use the same timing mechanisms as in thecase of periodic use.

FIG. 20 shows a signal flow diagram of an example periodic spectrum useprocedure 2000 for a T1U 2008. The system in FIG. 20 includes T3U 2002,T2U 2004, SSM 2006 and T1U 2008. The T1U 2008 may send a message 2010 tothe SSM 2006 regarding the expected T1U spectrum use and its timing. Forexample, the T1U 2008 may determine and indicate to the SSM 2006 that itneeds to reclaim the spectrum assigned to the lower tier users after anadvance notice time T_(adv). The SSM 2006 may determine an assignmenttiming plan, 2012, based on message 2010 and may provide T2 and T3assignments and TTLs based on the assignment timing plan, 2014, to theT2U 2004 and the T3U 2002.

The SSM 2006 may send TTL renewal messages, 2016 and 2018, to the T3U2002 during a T_(adv) time period when the spectrum is not needed by theT1U 2008. Following the TTL expiry for the T3U 2002 and the end of theT2U assignment validity time for the T2U 2004, the T3U 2002 and T2U mayrespectively release spectrum, 2020 and 2022. The T2U 2004 may send aconfirmation message 2024 to the SSM 2006 to confirm that the spectrumwas released. The T1U 2008 may then reclaim and use the releasedspectrum, 2026.

According to an embodiment, there may emerge an unexpected need for aT1U to use more spectrum while the unused spectrum of the T1U has beenassigned to other users. In other words, the T1U may need some of itsspectrum back. In this case, the T1U may send a reclaim request to theSSM. FIG. 21 shows an example 3-tiered spectrum model where a T1U needssome bandwidth back that has been assigned to lower tier users.According to the example in FIG. 21, the incumbent has a need foradditional spectrum starting at time t₁, at which time reassignment ofspectrum for the T3U and/or the T2U may be used.

Approaches for handling T1U spectrum reclaim from the spectrumassignment point of view are described below.

According to an approach, the reclaim amount may be less than thespectrum in the buffer (e.g. the spectrum assigned to the T3U). In thiscase, only T3U assignments may be affected immediately. To carry out thereclamation, the SSM may not send a TTL renewal and/or may send evacuatecommands to T3U(s). If evacuation commands are available, the approachmay be as fair towards the T3Us as possible, when some of them are leftwithout spectrum, or their bandwidths may be reduced. The SSM may needto “rebuild” sufficient buffer after the reclaim.

According to another approach, a spectrum change may be more than thespectrum in the T3U buffer. In this case, in addition to all T3Us, theT2Us may also be affected. Action may depend on the timing. For example,it may depend on how long in advance, T_(adv), the T1U informs the SSMregarding the need for additional spectrum, and whether T_(adv) islonger or shorter than the TTLs and/or the assignment validity times.

If T_(adv)>TTL, then TTLs may expire during T_(adv) and the assignmentrenewals may be done so that the T1U gets sufficient spectrum. This mayassume that T3Us are using spectrum based on TTLs, and that T2Us usespectrum based on TTLs or assignment validity times. For a T2U in thisscenario, some or all of the T2U's may not receive a TTL renewal messageand/or may receive an evacuate command. Additionally, the bandwidthassigned to T2Us may be reduced. For example, a T2U's bandwidth may becut or reduced by a given percentage. This may be done by the SSMsending a reassignment command to the T2U.

The impact of the bandwidth reclaim may be shared between T2Us in thetime domain. For example, the time in which the T1U may use the spectrummay be divided into portions, and in each portion one of the T2U eithermay not have its TTL renewed (or may receive an evacuation message), ormay have its bandwidth cut. This may be implemented by the SSM sendingspectrum reassignments for each time portion.

If T_(adv)<TTL, then some TTLs may expire only after T_(adv) may havepassed. In this case a “kill switch” approach may be employed, such thatthe SSM may send an immediate evacuate command to the affected usersbefore the TTLs expire. Use of evacuate commands may allow usage oflonger TTLs, while allowing quick evacuation of spectrum for reclaim.

In all the above cases, the QoA of T2Us may be affected. This may beavoided, but if it happens, there may be a need for compensation. Therisk of such spectrum availability reduction may be embedded beforehandin the price paid by a T2U for its spectrum. If possible, the timeparameters may be chosen such that T_(adv)>TTL.

FIG. 22 shows a signal flow diagram of an example spectrum reclaimprocedure 2200 for a T1U 2208. In this example, it is assumed that theT3U 2202 uses the TTL mechanism, T_(adv)>TTL, and the T2U 2204 usesassignment validity time mechanism, such that the SSM 2206 may send areassignment or evacuate command to the affected T2U 2204.

In the example of FIG. 22, spectrum assignments may initiate the startof validity times and TTLs, 2210, for the T2U 2204 and the T3U 2204. TheT1U 2208 may send a spectrum reclaim message 2212 to the SSM 2206indicating an advance notice time for the reclamation. The SSM 2206 maydefine reassignments and evacuations of spectrum, 2214, in accordancewith the spectrum reclaim message 2212. If the SSM 2206 receives a TTLrenew request message, 2216, from the T3U 2206, the SSM may not renewthe assignment. In the case of no renewal, the T3U 2202 may stoptransmissions and release the spectrum, 2218.

Meanwhile, the SSM 2206 may send a reassignment and/or evacuationcommand 2220 to the T2U 2204, which may reconfigure its network torelease spectrum, 2222. The T2U 2204 may send a confirmation message2224 to the SSM 2206 to confirm that the spectrum was released. The SSM2206 may in turn send a spectrum released message 2226 to the T1U 2208to notify the T1U 2208 that the spectrum it requested is available. Atthe end of the advance notice time, the T1U may use the releasedspectrum, 2228.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A method for enabling new user spectrumauthorizations in a multi-tiered shared spectrum system, performed by ashared spectrum manager (SSM), the method comprising: sending, to aregulator, a request for administrative information; receiving, from theregulator, a policy including at least one of: priorities for spectrumusers, guidance on making spectrum available for spectrum users in eachtier, timing information, or reclaim requirements; receiving, from theregulator, user authorization criteria to enable the SSM to issuespectrum usage authorizations to spectrum users on behalf of theregulator; updating a database based on the policy and userauthorization criteria; receiving a spectrum request from at least onespectrum user with an associated priority; and in response to thereceived spectrum request, assigning available spectrum to the at leastone spectrum user based at least on the policy and user authorizationcriteria.
 2. The method of claim 1, further comprising: receiving, fromthe regulator, an authorization to issue individual authorizations tousers on behalf of the regulator.
 3. The method of claim 1, furthercomprising: sending, to the regulator, a confirmation message confirmingreceipt of at least one of: the policy or user authorization criteria.4. The method of claim 1, further comprising: receiving, from theregulator, updated administrative information including at least one of:an updated policy, updated user authorization criteria, or adjacentspectrum usage.
 5. The method of claim 1, further comprising:periodically sending, to the regulator, reports on at least one of: useractivities, issued user authorizations, user assignments, occurrences ofinterference experienced by users, spectrum use, or spectrum efficiency.6. The method of claim 1, wherein spectrum users include at least oneof: tier 1 users (T1Us), tier 2 users (T2Us), and tier 3 users (T3Us).7. The method of claim 1, further comprising: assigning a unique useridentification to the at least one spectrum user.
 8. A shared spectrummanager (SSM) configured to enable new user spectrum authorizations in amulti-tiered shared spectrum system, the SSM comprising: a transmitterconfigured to send, to a regulator, a request for administrativeinformation; a receiver configured to receive, from the regulator, apolicy including at least one of: priorities for spectrum users,guidance on making spectrum available for spectrum users in each tier,timing information, or reclaim requirements; the receiver configured toreceive, from the regulator, user authorization criteria to enable theSSM to issue spectrum usage authorizations to spectrum users on behalfof the regulator; a processor configured to update a database based onthe policy and user authorization criteria; the receiver configured toreceive a spectrum request from at least one spectrum user with anassociated priority; and in response to the received spectrum request,the processor configured to assign available spectrum to the at leastone spectrum user based at least on the policy and user authorizationcriteria.
 9. The SSM of claim 8, wherein the receiver is furtherconfigured to receive, from the regulator, an authorization to issueindividual authorizations to users on behalf of the regulator.
 10. TheSSM of claim 8, wherein the transmitter is further configured to send,to the regulator, a confirmation message confirming receipt of at leastone of: the policy or user authorization criteria.
 11. The SSM of claim8, wherein the receiver is further configured to receive, from theregulator, updated administrative information including at least one of:an updated policy, updated user authorization information, or adjacentspectrum usage.
 12. The SSM of claim 8, wherein the transmitter isfurther configured to periodically send, to the regulator, reports on atleast one of: user activities, issued user authorizations, userassignments, occurrences of interference experienced by users, spectrumuse, or spectrum efficiency.
 13. The SSM of claim 8, wherein spectrumusers include at least one of: tier 1 users (T1Us), tier 2 users (T2Us),and tier 3 users (T3Us).
 14. The SSM of claim 8, wherein the processorand transmitter are further configured to assign a unique useridentification to the at least one spectrum user.